Party composition for Ruin/Ponderous?

[Tol1as]

Finally beat the game on all mid difficulty settings, so now I'm aiming for the hardest (though not without saving anywhere thats just masochistic).

My first win I used a Brawler/Guardian as my main, Reeve as an Ignis Knight/Warpblade (very strong combo, truly heinous aoe and mobility), another dude as Sharpshooter/Stormshot, a human Warden/Balancer (survival up the ass) and a Scurrio Sorcerer/Gatekeeper focused on lightning (always acted first, great AoE).

This time I'm thinking of doing something like,

Unmaker/Defiler for main (or maybe Ravager instead of one of the other two), with +10 mp race
Reeve as Blade/Krakenslayer
Some sort of buffer, maybe Warden/Minstrel (is the game even beatable without warden?)
??? (maybe a gun+sword shiftcloak + something else)
??? (some sort of windmage? wind seems very strong with the push damage, esp. vs crowds)

Feel free to throw some ideas.

[Moon Fairy Kyra]

If you want some real spicy options that I used for Ruin Mode.

Shiftcloak/Swashbuckler is a real fancy mobility based combo I found that can use the Adaptability Passive to switch between Shiftcloak/Rogue for debilitating and Shiftcloak/Blade for a more melee focus while Swashbuckler helps with dual wielding a Dagger/Sword and Crossbow/Pistol.

Ravager/Berserker is literal ook-ook. Although I have a suicidal combo I used that was Breaker/Ravager with Imposing. It existed to be a tanky debilitating gorilla that'd focus on just breaking whatever they could rather than attempting to kill. Killing came later or if it was reasonable over B R E A K I N G E V E R Y T H I N G

Could also try and run a weird combo like Elementalist/Balancer with a Krakenslayer Support that intentionally electrifies any water made to keep the Elebalancer Healing and being a portable stun walker.

Mechanist/Gatekeeper with Barrier + Barrier Shield. A literal gatekeeper. Use Portable Wall and Set Traps alongside Barrier and your Barrier Shield to just outright have some oppressive ZoC.
Effective but admittedly a reasonably boring prospect to many, since it's more of a prebuff/setup kind of deal for max effectiveness. Might take too long to see some fruition in actual combat, and might seem too meta/effective outside of it.

Just some random ideas. Although when I attempted the third one, making enough water to not require it to just be an inferior close range stunner or damage dealer was quite hard. Still seeing what I can do about it

[McFrugal]

You could beat the game without Warden on Ruin but you'd probably want to get Guard status via Sailor. It may even be possible to beat the game without Guard status at all, but it would be painful.
Really, I've found that party composition doesn't matter much beyond having a good defensive core. You just have to survive, and deal damage to the enemy while surviving.
Defense comes in Guard/Steady, Ward, Growth, life shards and splints, Negate, and Mighty Guard. A way to resurrect party members is also good. Disabling abilities like freeze, stun, disable, and immobilize (or large movement penalties in some situations, such as Oil and Trip Up) can also serve as a layer of defense, but it's hard to rely entirely on that.

For offense, possibly the best dps in the game is from Hurl Weapon on someone with Heavy Bandolier and a bag of hammers, but that's single target only. For multiple target dps, Whirl is a surprisingly good option, as well as Gust and Gate Barrage. A wind specialist can be very effective. Lightning isn't too bad either, since you can use shock bolt for instant multitarget damage or any of the Krakenslayer abilities, and Lightning(the spell) is quick enough to hit multiple targets reliably. Condensate is another instant aoe spell that does decent damage and combos well with lightning or ice.
For non-elemental aoe your options are a lot more limited. Bladestorm, Quake, Frenzy, Multishot... Smite and Hurricane Kick too I guess.

[Greg_Murrell]

No, the game is not beatable without Warden. : )

McFrugal's got the right idea. Though I'll chime in that stun-locking (preferably from a bow), and especially freeze-locking, are almost always a very viable form of offense. If you're MP-heavy, Prayer, preferably multiple sources of it, is a must for longer fights. Also, don't forget Warden's Barrier as another great form of defense.

For your Ruin unit, Unmaker is really more suited for melee units with its close-range attacks, Drain technique, and Ruin Aura passive, while Defiler is more of a true artillery unit. Mixing Unmaker with Ravager is an option. Also, look into Tactician's "Now!" technique. The rest of Tactician is optional, but an Ability Crest'd "Now!" on your support unit is superb.